Typical household and commercial alarm systems employ numerous motion detectors as a way of ensuring that any intruder will be detected as he moves about, regardless of how the premises were entered and regardless of whether such entry occurred before the alarm was on (such as during normal business hours), or by cutting glass of an alarmed window, or the like. Such systems typically provide for the user to bypass portions of the alarm system, so that the perimeter portion of the alarm system can be on while authorized people are within the secure space, without setting off the alarm. However, in large houses, it sometimes becomes difficult to remember to change the bypass system if an authorized person is moving about. Thus, in a house having an all-glass walkout basement that is adjacent to a deep woods, it may be desired to leave the motion detectors armed, along with any sliding doors in the basement, while the middle floor of the house is occupied. However, should someone forget and enter the basement without altering the alarm system, the alarm system will be triggered and the person may have a difficult time reaching the control panel in time to avoid an automatic telephone call alert. It is known that numerous false alarms cause automatic alerts to be treated casually, and are therefore to be avoided.
Dogs, cats and other pets in the house preclude use of presence detectors in alarm systems; or, such detectors must be bypassed except when the pets leave (e.g., during vacation).
The use of "smart badges" which transmit ID numbers, for tracking the whereabouts of personnel in a facility, can be thwarted by simply taking the badge off.